London – A Mexican wrestler known as Silver King died in the ring during an appearance in London, the venue confirmed on Sunday.

“Last night Silver King sadly lost his life during an event at the Roundhouse,” said a statement posted on Twitter by the venue in the north London borough of Camden.

“At this stage the details are still being investigated so we don’t have more information we can share,” it added.

The 51-year-old, whose real name was Cesar Cuauhtemoc Gonzalez Barron, was a star on Mexico’s Lucha Libre wrestling scene.

Last night Silver King sadly lost his life during an event at the Roundhouse. At this stage the details are still being investigated so we don’t have more information we can share. Our thoughts and condolences are with his family, friends and all of the Lucha Libre team.

— Roundhouse (@RoundhouseLDN) May 12, 2019

He may have suffered a heart attack, according to media reports.

Below is a statement from Lucha Libre World concerning the tragic loss of Silver King last night at the Roundhouse.

Rest In Peace Silver King, you will be sorely missed. pic.twitter.com/nzk9F1jfCa

— Lucha Libre World (@luchalibreldn) May 12, 2019

A video circulating on the internet shows Barron having difficulty getting up during an exhibition fight. Despite the referee’s request, he finally lies flat on the floor.

Eyewitnesses told the BBC that there was some confusion as to whether the incident was part of the show.

Barron began his career in the 1990s for World Championship Wrestling (WCW) in the US. He became famous for playing the villain Ramses in the film “Nacho Libre.”